What mechanism allows a router to respond to an ARP request for a remote host?

The mechanism that allows a router to respond to an ARP request for a remote host is Proxy ARP. When a device on a local network sends out an ARP request to determine the MAC address of a remote IP address, Proxy ARP enables the router to respond as though it were on the same local subnet as the requesting device.

This is particularly useful in scenarios where the remote host is not directly reachable on the local network. By responding to the ARP request, the router effectively allows devices on one subnet to communicate with devices on another subnet without needing direct knowledge of the interconnecting network's topology or the specifics of any subnets beyond their own.

Proxy ARP works by listening to ARP requests and replying to them if the destination IP is associated with one of the router's interfaces. This transparency can simplify routing configurations, especially in environments where complex subnetting exists, providing continuity for devices that may not be aware of the broader network topology.

The other options, such as Gateway DP, Reverse ARP (RARP), and Inverse ARP (IARP), do not serve the same purpose of facilitating communication between different subnets through the response to ARP requests for remote hosts. Each serves distinct functions in networking, but